SPL Dynamics PRO-300D4

12″ subwoofer · dual 4 Ω · 600 W RMS

34 HzFs, resonance

0.52Qts

1.41 ft³Vas

0.51″Xmax

600 WRMS

Source	web.archive.org · manufacturer data
Checked against source	October 2026
Thiele/Small parameters	not in the spec sheet: Re, Sd — typical value for the size used
Mounting dimensions	2 of 4 — missing: frame outer diameter, magnet diameter; the designer will use an estimate

Recommended box

For a sedan, one sub, 600 W. It’s the same math as the designer’s step-by-step mode, where you can fit the box to your space, vehicle and amp and get plans, a cut sheet and DXF.

Sealed

smaller, tighter

1.02 ft³ (29 L)

Net volume

Bass character (Qtc)	Tight and punchy · 0.80
Fc	52 Hz
F3 (−3 dB, no cabin gain)	49 Hz
Example box (outside)	14 3/16″ × 14 3/16″ × 13 7/16″

Open sealed box in designer

Ported

deeper, louder

1.20 ft³ (34 L)

Net volume

Tuning (Fb)	34 Hz
Port	slot 1 9/16 × 14 5/16″, 39 9/16″ long
Port velocity at 600 W	52 ft/s
F3 (−3 dB, no cabin gain)	35 Hz
Example box (outside)	21 3/8″ × 15 3/4″ × 13 9/16″

Open ported box in designer

Deeper: 2.93 ft³ (83 L) tuned to 30 Hz, 31 1/2″ × 15 3/4″ × 16 7/16″ outside — a bigger box with flatter deep bass. Open in the calculator

Where to buy Amazon

Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Size	12″
Voice coils	dual 4 Ω
RMS power	600 W
Fs	34 Hz
Qts	0.52
Qes	0.6
Qms	3.9

Vas	1.41 ft³
Re (one coil)	≈ 3.4 Ω
Sd	≈ 76 in²
Xmax	0.51″
EBP	57 — sealed or ported calc.
Sensitivity, 1 W / 1 m	86.2 dB calc.

Mounting dimensions

Cutout diameter	11 1/8″
Mounting depth	6 7/16″

“≈” means the value isn’t in the spec sheet and a typical value for the size is used; “calc.” means it’s calculated from the published parameters. Check the manufacturer’s spec sheet before you build.

Data sources

web.archive.org/web/20070711013554/http://www.spldynamics.fi:80/pro-sub/pro-300d

Other SPL Dynamics 12″ models

SPL Dynamics PRO-12D2 MK3 12″ · dual 2 Ω
SPL Dynamics PRO-12D2 MK4 12″ · dual 2 Ω
SPL Dynamics PRO-12D4 MK3 12″ · dual 4 Ω
SPL Dynamics PRO-12D4 MK4 12″ · dual 4 Ω
SPL Dynamics PRO-300D2 12″ · dual 2 Ω
SPL Dynamics SPL-300D1A 12″ · dual 1 Ω
SPL Dynamics SPL-300D2 12″ · dual 2 Ω
SPL Dynamics SW-300D2 12″ · dual 2 Ω
SPL Dynamics SW-300D4 12″ · dual 4 Ω
SPL Dynamics V-12S 12″ · 4 Ω
SPL Dynamics V-12S4 12″ · 4 Ω
SPL Dynamics V-300D2 12″ · dual 2 Ω

Similar 12″ subwoofers from other brands

Close in Fs, Qts and Vas — a box of similar volume will suit them.

Machete M12 D2 Sport 0.99 ft³ sealed · 1.20 ft³ ported
Machete M12 D1 Sport 0.95 ft³ sealed · 1.20 ft³ ported
Pioneer TS-W307D4 1.06 ft³ sealed · 1.17 ft³ ported
Machete M12 D4 0.99 ft³ sealed · 1.20 ft³ ported
Hifonics ZSPL12D2 1.20 ft³ sealed · 1.27 ft³ ported
Soundstream T7.124 1.27 ft³ sealed · 1.27 ft³ ported

FAQ

What box does the SPL Dynamics PRO-300D4 need?

Recommended net volume: 1.02 ft³ sealed, 1.20 ft³ ported tuned to 34 Hz — for one sub in a sedan at 600 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the SPL Dynamics PRO-300D4 Thiele/Small specs?

Fs 34 Hz, Qts 0.52, Vas 1.41 ft³, Xmax 0.51″.

What is the SPL Dynamics PRO-300D4 mounting depth?

Mounting depth is 6 7/16″, cutout diameter 11 1/8″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the SPL Dynamics PRO-300D4 handle and how do I wire it?

RMS power rating: 600 W. Dual 4 Ω voice coils: series gives 8 Ω, parallel gives 2 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.